Overall goals of this project are to define the nature of genes which code for, or otherwise affect the structure of immunoglobulins(Igs) and to understand the processes which regulate Ig-gene expression and which lead to synthesis of highly specific antibody-molecules. We prepare immunological reagents which detect structural differences between genetically controlled polymorphic forms of rabbit Igs (Ig allotypes). We use immunological, chemical and molecular genetic approaches to define the Ig-structural differences and to learn more about the chromosomal organization of Ig genes, and the regulated expression of antibodies and antigen-specific surface receptors on lymphocytes. Inheritance patterns and the levels of regulation of phenotypic expression of alleles and chain types are investigated by breeding experiments, by studies of ontogeny and differentiation of cells of the rabbit immune system and by direct molecular genetic analyses. Two major new efforts which are planned will involve the use of recombinant DNA molecules to: 1) examine genome organization by isolation of rabbit Ig-genes and analysis of variable and constant region DNA sequences as well as adjacent sequences; and 2) identify nuclear RNA precursors and their processing steps in the production of immunoglobulin mRNA.